Objectives: Assessment of intra- and interobserver agreement in multiple intraluminal impedance (MII) measurement between investigators from different institutions.
Methods: Twenty-four 18- to 24-hour MII tracings were randomly chosen from 4 different institutions (6 per center). Software-aided automatic analysis was performed. Each result was validated by 2 independent investigators from the 4 different centers (4 investigator combinations). For intraobserver agreement, 6 measurements were analyzed twice by the same investigator. Agreement between investigators was calculated using the Cohen kappa coefficient.
Results: Interobserver agreement: 13 measurements showed a perfect agreement (kappa >0.8); 9 had a substantial (kappa 0.61–0.8), 1 a moderate (kappa coefficient 0.41 to 0.6), and 1 a fair agreement (kappa coefficient 0.11–0.4). Median kappa value was 0.83. Intraobserver agreement: 5 tracings showed perfect and 1 showed a substantial agreement. The median kappa value was 0.88.
Conclusions: Most measurements showed substantial to perfect intra- and interobserver agreement. Still, we found a few outliers presumably caused by poorer signal quality in some tracings rather than being observer dependent. An improvement of analysis results may be achieved by using a standard analysis protocol, a standardized method for judging tracing quality, better training options for method users, and more interaction between investigators from different institutions.
*Klinik für Kinder- und Jugendmedizin, St Josef-Hospital, Universitätsklinik der Ruhr-Universität Bochum
†Klinik für Kinder- und Jugendmedizin, Universitätsklinikum RWTH Aachen
‡Klinik für Kinder- und Jugendmedizin, Klinikum Worms
§Kinder- und Jugendklinik, Universitätsklinikum Erlangen, Germany.
Address correspondence and reprint requests to Denisa Pilic, Klinik für Kinder- und Jugendmedizin, St Josef Hospital, Universitätsklinik der Ruhr-Universitat Bochum, Alexandrinenstr 5, 44791 Bochum, Germany (e-mail: Denisa.Pilic@gmx.de).
Received 13 November, 2010
Accepted 20 February, 2011
Dr Pilic has served on the speakers’ bureau of Tecnomatix Medical; Dr Wenzl has received research support from AstraZeneca, Sandhill Scientific, and Tecnomatix Medical, has been a consultant to Sandhill Scientific, and has served on the speakers’ bureaus of Tecnomatix Medical and Reckitt Benckiser. The other authors report no conflicts of interest.